Refrigerant metering system

ABSTRACT

An improved injector type refrigerant metering device for use in place of standard thermostatic or automatic expansion valves, high or low side floats, capillary tube metering devices or any other conventional method of metering liquid refrigerant from the high side to the low side of a compression type refrigeration system.

Unite States ate 1191 Brandt Sept. 1 1, 1973 1 REFRIGERANT METERING SYSTEM 2,462,329 2/1949 Majonnier 62/512 2,859,596 11/1958 Evans 62/512 1761 lnvemor- Paul 1" 5202 Fkwer 3,557,570 1/1971 Brandt 62/278 Phoenlx, Ariz. 85018 I [22] Filed: July 28, 1971 Primary ExaminerMeyer Perlin pp No 166 748 Attorney-Warren F. B. Lindsley 7 TRA T [52] 11.8. CI 62/278, 62/500, 62/512 [5 ABS C [51 Int. Cl. F251) 47/00 An improved injector yp refrigerant metering device [58] Field of Search... 62/512, 278, 500, for use in Place of Standard thermostatic Or automatic 62/216 expansion valves, high or low side floats, capillary tube metering devices or any other conventional method of 5 R f n Cited metering liquid refrigerant from the high side to the low UNITED STATES PATENTS side of a compression type refrigeration system.

2,132,932 10/1938 Boileau 62/512 3 Claims, 2 Drawing Figures REFRIGERANT METERING SYSTEM BACKGROUND OF THE INVENTION This invention relates to refrigeration systems and is particularly directed to an improvement of the injector type refrigerant metering apparatus described and claimed in U. S. Pat. No. 3,557,570.

DESCRIPTION OF THE PRIOR ART Heretofore, nitrogen cold traps in the standard type of refrigerant metering devices'frequently failed because of the low velocity of the refrigerant in the evaporator cold trap and the resultant small amount of oil in the refrigerant needed for lubrication purposes.

Although the refrigerant metering device of U. S. Pat. No. 3,557,570 increases the refrigerant velocity in the evaporators of conventional refrigeration systems, it can be further improved by reducing the number of nozzles and expansion zones in the evaporator while still increasing the refrigerant velocity and the oil agitation of the evaporator over the standard prior art systems.

SUMMARY OF THE INVENTION In accordance with the invention claimed, an improved refrigerant metering device is provided.

It is, therefore, one object of this invention to provide a refrigerant evaporator which increases the velocity of the refrigerant while reducing the number of parts of the prior art evaporators.

Another object of this invention is to provide an improved injection type refrigerant metering device which increases the heat transfer of the evaporator while keeping oil droplets in suspension in the refriger BRIEF DESCRIPTION OF THE DRAWING The present invention may be more readily described by reference to the accompanying drawing in which:

FIG. 1 is a system diagram, partly in section, showing an injector metering system operating in conjunction with a conventional type compression refrigeration system and embodying the invention; and

FIG. 2 is a cross sectional view of FIG. 1 taken along the line 2-2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring more particularly to the drawing by characters of reference, FIGS. 1 and 2 disclose a conven tional type refrigeration system 8 having a known compressor 9 connected by means of a pressure discharge line 10 to the input of a condenser 11. Condenser 11 is connected through a condenser discharge line 12, valve 13 and a dehydrator 14 to a refrigerant evaporator 15. Evaporator 15 is connected through a return suction tube 16 and valve 17 to compressor 9.

The refrigerant evaporator, in this particular example, comprises a conventional nitrogen cold trap 18, the top of which is connected to a large return tube 19 which is connected through an injection head 20 of the refrigerant evaporator 15 to the suction line 16 of compressor 9.

The injector head 20 is inserted in a leg 21 of a hollow T-shaped housing or main valve body 22 and is suitably secured therein by a compression nut 23. Valve body 22 supports within its T-shaped arm 24 a venturi tube '25 which is connected to and extends within tube 19 and discharges into a coaxially arranged inner tube 19' in tube 19 and is axiallyaligned at its other end with a capacity control nozzle 27. Nozzle 27 may be soldered within an opening in arm 24 to be axially aligned with venturi tube 25.

The injection head 20 secured to main valve body 22 includes the suction and oil scoop return and exchanger assembly 28 having the liquid heat exchanger line 29 connected to condenser discharge line 12 and the line 30 connected to the compressor return suction line 16. A cone-shaped ceiling 31 forms part of cap 32 which closes the injector head 20 as shown.

A hot gas defrost mechanism 33 is connected through line 34, hot gas solenoid valve 35 and line 36 to the compressor pressure discharge line 10.

OPERATION through tube 19 to the bottom of the refrigerant evaporator 18. Part of the refrigerant evaporated in evaporator 18 and the mixture of the evaporated refrigerant and liquid refrigerant returns to the injector head through openings 39 in the tube 19, annular spaces 40 and 41 and passageways 42 in the venturi tube support bushing 43 carried in the main valve body 22.-

Evaporated refrigerant in vaporform rises to the top of the refrigerant liquid level in injector head 20 to be returned to compressor 9 through suction line 45. As shown, scoop 46 is connected to the compressor return suction line. Liquid refrigerant which is not evaporated is driven back through evaporator 18 by high velocity liquid refrigerant leaving injector nozzle 27 through venturi tube 25 and tube 19. Since three to four times more refrigerant is fed to evaporator 18 than what is evaporated, a continual agitation is maintained in the evaporator.

It will be further. noted that this agitation prevents oil separation from the refrigerant in the evaporator which returns the oil and refrigerant mixture to the injector head 20, this agitation not occurring with a conventional expansion valve system.

The passageof evaporated refrigerant through the injection head 20 to the suction of the oil scoop and exchange assembly 28 returns any excess oil back to the compressor by high velocity suction gas at the inlet 46 of the oil scoop assembly.

Fast defrosting and warm-up of the system for servic ing or for close temperature control of the evaporator 18 may be accomplished by energizing hot gas solenoid valve 35 which causes hot discharge gas to enter the evaporator through tube 36;. This hot gas is discharged into a pocket 47 in injection nozzle 27, as shown in FIG. 1. The high pressure hot gas refrigerant is forced through angular space 48 around nozzle 27 into the venturi tube 25 to circulate the same as when liquid refrigerant is fed through nozzle 27. When hot gas solenoid 35 is energized, the high pressure gas enters the evaporator through orifice 48. This raises the pressure in the evaporator side of the system and reduces the high side pressure, which reduces the pressure differential across nozzle 27. This reduction in pressure differential reduces the follow-up liquid refrigerant through the orifices of nozzle 27 to nearly zero and only hot gas is fed into the evaporator when hot gas solenoid 35 is energized. Hot gas is condensed in the evaporator until the temperature in the evaporator is raised above freezing. Vapor refrigerant is pumped back to the condenser and stored in the condenser after condensing. Because of the reduction in this pressure the liquid refrigerant will not pass through nozzle 27. Nozzle 27 comprises a pair of coaxially arranged orifices, namely central orifice 37 and outer orifice 48, both of which discharge into venturi tube 25.

Although but one embodiment of the present invention has been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

I claim: a

1. An injection type refrigerant metering device comprising in combination:

a main valve body having a valve chamber,

a first supply tube,

said valve body supporting one end of said first supply tube in communication with said valve chamher,

a second supply tube,

the other end of said valve body being connected to said second supply tube,

the other end of said second supply tube being arranged to discharge within an evaporator,

an evaporator,

a venturi tube mounted in said valve body and having its input opening in communication with said valve chamber,

said first supply tube discharging into the input opening of said venturi tube,

a capacity control nozzle in said valve chamber also discharging into the input opening of said venturi tube,

an injection head on said valve body,

an oil collector, return and heat exchanger including a suction line mounted on said injection head in communication with said valve chamber,

a liquid heat exchanger line forming part of the suction line of said oil collector, return and heat exchanger,

and a line connecting said liquid heat exchanger line to said valve chamber,

said capacity control nozzle provided with a pocket which discharges through said capacity control nozzle into said venturi tube.

2. The injection type refrigerant metering device set forth in claim 1 wherein said capacity control nozzle comprises a pair of coaxially arranged orifices the center one of which discharges the refrigerant into said venturi tube and the outer one of which discharges the contents of said pocket of said capacity control nozzle into said venturi tube.

3. The injection type refrigerant metering device set forth in claim 1 in further combination with: means for discharging hot refrigerant into said valve chamber for discharge through said capacity control nozzle, said means discharges hot refrigerant into said pocket. 

1. An injection type refrigerant metering device comprising in combination: a main valve body having a valve chamber, a first supply tube, said valve body supporting one end of said first supply tube in communication with said valve chamber, a second supply tube, the other end of said valve body being connected to said second supply tube, the other end of said second supply tube being arranged to discharge within an evaporator, an evaporator, a venturi tube mounted in said valve body and having its input opening in communication with said valve chamber, said first supply tube discharging into the input opening of said venturi tube, a capacity control nozzle in said valve chamber also discharging into the input opening of said venturi tube, an injection head on said valve body, an oil collector, return and heat exchanger including a suction line mounted on said injection head in communication with said valve chamber, a liquid heat exchanger line forming part of the suction line of said oil collector, return and heat exchanger, and a line connecting said liquid heat exchanger line to said valve chamber, said capacity control nozzle provided with a pocket which discharges through said capacity control nozzle into said venturi tube.
 2. The injection type refrigerant metering device set forth in claim 1 wherein said capacity control nozzle comprises a pair of coaxially arranged orifices the center one of which discharges the refrigerant into said venturi tube and the outer one of which discharges the contents of said pocket of said capacity control nozzle into said venturi tube.
 3. The injection type refrigerant metering device set forth in claim 1 in further combination with: means for discharging hot refrigerant into said valve chamber for discharge through said capacity control nozzle, said means discharges hot refrigerant into said pocket. 